JP2015059340A - Crushing claw of crusher for building breakup, and welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crushing claw of a crusher for building breakup and a welding method, in which a claw tip part of a crushing claw of a crusher that is used for building breakup is formed from the material of high hardness and high toughness, for improved wear resistance.SOLUTION: In order to improve wear resistance of a crushing claw which constitutes a tip part of an arm of a crusher for building breakup, SKD 61 is used as the material of high hardness and high toughness from among hot mold tool steel. By welding the SKD 61 to the tip end of the crushing claw, a claw tip part of SKD 61 is formed.

Description

  The present invention relates to a crushing claw and a welding method of a crushing machine for building dismantling that improves the wear resistance of a claw toe portion used in a crushing machine for dismantling a building.

  In recent years, buildings that are subject to demolition work have considerably higher concrete strength and robustness than buildings built during the period of high economic growth. For this reason, it is requested | required that the crusher used when demolishing a building should use the claw which has high robustness and abrasion resistance.

  In recent years, buildings to be demolished have increased demand for the SRC structure in addition to the RC structure, and with the increase in the number of buildings, the number of sites where it is necessary to raise the dismantling machine to the upper floors is also increasing. Therefore, in such a site, it is necessary to extend the life of the crushing claw of the crusher so that the dismantling work can be completed without maintenance from the upper floor where the weight dismantling machine is installed to the ground floor.

  Furthermore, in the dismantling site, the wear resistance and toughness of the crushing claw provided in the crusher are regarded as important so that fine work such as sorting work of dismantled objects and gripping of steel frames, steel plates, etc. can be performed It has become.

  Here, the present state of the crushing claws used in the crusher as described above will be described below.

  (1) As a conventional crushing claw, cast iron products are mainly used, and there is a problem that the quenching hardness of the claw tip is lowered by welding heat in the work of welding and joining to the tip of the crusher arm.

  (2) Assuming that the Brinell hardness (HB) of the wear-resistant steel plate is equivalent to 500, Everhard steel, Sumihard steel, Welhard steel, Haldox steel, etc. may be used for the toes, but each steel material is heated. It is weak and decreases in hardness at 250 ° C. In addition, the hardness of each steel material decreases due to the thermal effect of gas cutting. Furthermore, wear of the claw tip of the claw claw causes a difficulty in performance of keeping the claw gap between the claw toes zero.

  (3) The conventional method in which wear resistance is provided by applying surface hardening rod welding to the claw tip of the crushing claw is only two or three surface hardening welding, and if the hardening rod layer is worn, The base material whose hardness is reduced by heat causes a disadvantage that the wear progresses at a stretch.

  (4) As described above, the conventional crushing claw has a short period of holding the claw gap between the toes at zero, so it may have wear resistance by taking a large cross-sectional area of the tip shape of the toes. . However, since the tip of the toe is not sharp, the bite into the demolished material becomes worse, and when the toe does not bite into the demolished material in this way, the toe slides on the concrete surface by the thrust of the cylinder, so wear progresses due to sliding friction It will be.

  Thus, the conventional toe used for the crusher has various problems. Therefore, as a result of investigating known patent documents in order to solve such problems, there is a technique for improving the working efficiency of the crusher as described in Patent Document 1 described later. A technology for improving the hardness, toughness, etc. could not be found.

JP 7-26739 A

  The present invention has been made in view of the above circumstances, and improves the wear resistance by forming the toe portion of a crushing claw used in a crusher for dismantling a building from a material having high hardness and toughness. It aims at providing the crushing claw and welding method of the crusher for building demolition which were made.

  In order to solve the above-mentioned problems, the crushing claw of the building demolition crusher according to claim 1 of the present invention is to improve the wear resistance of the crushing claw constituting the tip of the arm of the building demolition crusher. The SKD61 is used as a material having high hardness and toughness from among the hot tool steel, and the toe portion by the SKD61 is formed by welding the SKD61 to the tip of the crushing claw.

  Moreover, the crushing claw of the crusher for building demolition according to claim 2 of the present invention is characterized in that the toe portion is formed by welding SKD61 to the tip of the crushing claw in claim 1.

  Moreover, the crushing claw of the crusher for building demolition in Claim 3 of this invention welds SKD61 which comprises a toe part to the front-end | tip of the crushing claw provided in the body separate from the arm of the crusher in Claim 1. A single crushing claw is formed by the above method, and the rear end of the single crushing claw is welded to a broken or worn tip portion of the arm.

  Furthermore, the welding method of the crushing claw of the crusher for building demolition according to claim 4 of the present invention is such that when the toe part is formed by welding the SKD 61 to the tip of the crushing claw, the tip of the crushing claw and the toe part by the SKD 61 A groove angle is provided at the rear end, and a gap is provided between the tip top of the crushing claw and the rear end top of the claw toe facing each other. The top of the claw claw is welded to the center of the top, and the tip of the claw claw and the rear end of the claw toe are attached with the flow stop plate applied to the side near the tip of the claw claw and the side near the back of the claw tip. It is characterized by welding to each other.

  In the present invention, in order to improve the wear resistance of the crushing claws constituting the tip of the arm used in the crusher, SKD61 is selected from hot tool steel as a material having high hardness and high toughness. The toe part is formed by welding the material to the tip of the crushing claw.

  As described above, in the present invention, SKD61 is used as a material having high hardness and high toughness from among hot die tool steel, and this SKD61 is welded to the tip of the crushing claw to thereby form the SKD61 on the tip of the crushing claw. It is set as the structure which formed the toe part by. Therefore, the wear resistance of the crushing claw can be improved by the high hardness and toughness of SKD61 acting on the toe portion of the claw claw.

  In addition, by welding SKD61 as the claw toe part of the crushing claw in this way, the claw toe part of the crushing claw is not rounded and worn in the crushing operation at the dismantling site, but the tip is pointed. A phenomenon of wear has been confirmed. Thus, when the tip of the claw claw has a sharp tip, it has the advantage of good bite into the concrete and improved crushing efficiency, reducing the frequency, labor and labor required for crushing claw maintenance. It is possible to improve the workability such as less burden on the machine.

In the Example of this invention, it is a side view which shows the state which welded SKD61 directly as a toe | tip part at the front-end | tip of a crushing nail | claw. (A) And (b) is a side view which shows the state which welded the rear end of the single crushing nail | claw to the front part to which the arm was damaged or was worn in the Example of this invention. It is a perspective view which shows the condition where a flow stop plate is applied and welded to the both sides | surfaces of the claw claw and the toe part by SKD61 in the Example of this invention. In the Example of this invention, it is a figure which shows the method of welding the toe | tip part by SKD61 to the front-end | tip of a crushing nail | claw, (a) is a top view, (b) is a side view. (A)-(d) is a side view which shows the procedure which welds the toe | tip part by SKD61 to the front-end | tip of a crushing claw in the Example of this invention. In the Example of this invention, it is a continuous cooling transformation curve regarding SKD61.

  Hereinafter, embodiments of the present invention will be described.

  As a result of pursuing a material suitable for the toe part having high hardness and toughness in order to improve the wear resistance of the toe part of the crushing claw used in the crusher, the present inventor, as described later, from among hot die tool steel So I decided to focus on SKD61.

  By the way, conventionally, SKD61 has a high weldability carbon equivalent (average value of 1.9%), and cracks are generated in a normal welding method.

  However, based on the original definition of welding, preheating the material creates active free atoms in the material, and the higher the preheating temperature, the more free atoms are produced and the weldability is improved. It has been known.

  Further, the present inventor has considered that the cause of cracking during welding described above is due to internal distortion due to a rapid temperature change during welding, particularly excessive quenching due to rapid cooling that occurs after welding. In subsequent research, annealing, quenching, and tempering were performed as sufficient preheating, temperature control between passes, and heat treatment after welding, thereby reducing the influence of welding heat and eliminating defects in the weld. The conclusion was obtained that good welding performance can be ensured.

  Furthermore, as a result of research by the present inventors, attention is paid to SKD61 as a material having high hardness and high toughness among hot die tool steels, and cracking does not occur by the welding method described later using this material. Good welding performance could be obtained.

  Note that SKD61 is a hot die tool steel represented by a JIS symbol, and DHA1 of Daido Special Steel Co., Ltd. is used as a JIS / SKD61 equivalent steel in this embodiment.

  Moreover, C, Si, Mn, Cr, Mo, and V are contained as main chemical components of SKD61. The content (%) of each component is as follows: C: 0.32 to 0.42, Si: 0.80 to 1.20, Mn: ≦ 0.50, Cr: 4.50 to 5.50, Mo = 1 0.01 to 1.50, V: 0.80 to 1.20.

  Here, the reason why the SKD 61 is selected as the welding material for forming the toe portion of the crushing claw used in the crusher will be described below.

  (1) SKD61 has a low carbon equivalent in hot tool steel. Note that cold mold steel and cutting tool steel have a large amount of carbon and are not suitable as welding materials for crushing claws.

  (2) Heat treatment can be performed in air. That is, annealing annealing, quenching, and tempering can be performed by air cooling, and the welded portion is not affected. On the other hand, in oil cooling and water cooling, since it becomes too rapid cooling, a welded part is affected. For this reason, although impact-resistant tool steel has high hardness, since it is oil cooling and water cooling, it is not suitable as a welding material.

  (3) Since SKD61 has a high tempering temperature (550 to 580 ° C.), it is hardly affected by heat. In alloy tool steels, the tempering temperature of many objects is air-cooled 180 ° C., and even if they are welded, the quenching hardness is lowered by welding heat, preheating, and postheating. On the other hand, SKD61 can substantially implement 600 ° C. as the recommended post heat of the surface hardening rod. As a result, there is an advantage that peeling of the surface hardening rod is difficult to occur. Also, as shown in FIG. 2 to be described later, a single crushing claw 2 is formed by welding an SKD 61 as a toe portion 3 to the tip of a crushing claw 2 provided separately from the arm 1, and the single crushing claw 2 is formed. When the rear end of the claw 2 is welded to the tip of the arm 1 that is damaged or worn, the welded portion 4b and the SKD61 (toe portion 3) welded to the tip of the crushing claw 2 are located at a distance from each other, so There is no decrease in hardness.

  (4) By the way, there are four types of hot mold steels that clear the above three points. That is, SKD6, SKD61, SKD62, and SKD7. These hot mold steels are air cooled and have a relatively low carbon content. Moreover, although the condition that the tempering temperature is high is satisfied, SKD61 has the highest hardness among these four types. In addition, the hardness of SKD61 is HRC47-52. For this reason, in the present invention, SKD61 was selected as the welding material.

  Next, a method for welding the SKD 61 to the tip of the crushing claw will be described.

  (1) As a welding form of the SKD 61, as shown in FIG. 1, the toe portion 3 is formed by directly welding the SKD 61 to the tip of the crushing claw 2 of the arm 1 (the welding portion 4a corresponds), As shown in FIG. 2 (a), by welding the SKD 61 as the toe portion 3 to the tip of the claw claw 2 made of high-strength steel or cast steel provided separately from the arm 1 (the welded portion 4a corresponds). When a single crushing claw 2 is formed and the rear end of this single claw claw 2 is welded to a damaged or worn tip of the arm 1 (as shown in FIG. 2B) (welding part 4b is applicable) There is.

  In the case of FIG. 1 described above, since the SKD 61 is directly welded as the toe portion 3 to the tip of the crushing claw 2, the technique of the present invention is required for the welding operation. On the other hand, in the case shown in FIGS. 2 (a) and 2 (b), by using the technique according to the present invention, the SKD 61 is welded to the tip of the crushing claw 2 as the toe portion 3, so that the single unit as shown in FIG. 2 (a) is obtained. This crushing claw 2 is formed, and this single crushing claw 2 can be distributed to the market as a product. A person who has obtained the single crushing claw 2 can weld the crushing claw 2 made of high-strength steel or cast steel to the damaged or worn tip of the arm 1 by a normal welding technique.

  (2) As described above, after welding SKD61 to the crushing claw that is the base material, by welding the surface hardening rod to the welded part and the base material side, the crushing claw that is the base material and the wear resistance of the welded part Can be improved.

  (3) After welding, heat treatment is performed at a heat treatment temperature described later.

  (4) The heat treatment uses flame hard (flame quenching) or a method equivalent thereto.

The conditions for the heat treatment temperature in the above welding are as follows.
Welding preheating temperature 450 ℃ ~ 600 ℃
Interpass temperature 600 ° C or higher Annealing temperature 820 ° C to 870 ° C Slow cooling quenching temperature 1020 ° C to 1050 ° C Air cooling tempering temperature 550 ° C to 580 ° C Air cooling

  Further, the size of the SKD 61 will be described. Particularly, in the case of the large split machine, when the gap between the two toes is worn to about 30 mm to 70 mm with respect to the toe wear, the use at the site of dismantling is almost unusable. Therefore, a small tip material having a size of about 40 mm × 40 mm × 100 mm (arm thickness) may be interposed between the worn toes.

  However, in the conventional toe, in order to avoid a decrease in hardness due to tempering, the size of the toe itself is as large as about 130 mm × 100 mm × 100 mm, which consumes a lot of welding rod consumption and welding time. It was. Conventionally, continuous welding cannot be performed due to an increase in temperature between passes due to welding heat input, and a waiting time has been required.

  On the other hand, when the welding material is SKD61, only a small member is required, and the amount of welding rods used can be reduced and the welding time can be shortened. Furthermore, there is an advantage that preheating, temperature control between welding passes, and heat treatment become easy.

  At present, the SKD 61 used as a welding material has a size of about 25 mm × 25 mm × 70 mm to 45 mm × 45 mm × 150 mm and is welded to the tip of the crushing claw.

  As described above, advantages of using SKD61 as a welding material for crushing claws will be described below.

  (1) The hardness of SKD61 is high at HRC 47-52, and the tip of the toe part is sharpened to some extent from the beginning, but the wear progresses and the tip shape does not wear round, and conversely the tip is sharp It has been confirmed that it will come. Thus, the crushing claw with the pointed toe portion sharpens the bite into the concrete and improves the crushing efficiency.

  In addition, when the bite of the toe portion is improved, the stress on the operator is reduced. Furthermore, there is an advantage that the burden on the crusher is reduced and the life of metal fatigue is extended. In addition, the burden on the hydraulic equipment and the hose is reduced, and wear of the pins and bushes that are the operating parts of the crusher is reduced. Furthermore, the environmental load is reduced by improving the efficiency of the dismantling site and improving the fuel efficiency of the hydraulic excavator.

  (2) The high hardness of SKD61, HRC47-52, is not limited to the surface of the claw toe part of the claw claw, and the internal core has the characteristics of high-hardness alloy steel, so that the core is easily baked. . Incidentally, the components of SKD61 are C, Si, Mn, Cr, Mo, and V, and have high hardenability.

  (3) Because of the high-temperature heat treatment, heat is transferred to the surface-hardened welded portion of the crushing nail, and the toughness of the hardened rod welded portion is increased and peeling is reduced.

  (4) As a result of using the crushing claw of the present invention welded with SKD61 as a toe part at the actual site, the crushing claw toe part (SKD61) most frequently used at the site of severe dismantling work may be missing. However, the welded portion has never been removed, and it is clear that the welding method of the present invention is robust.

  For example, the thrust generated by the 300φ cylinder (pressure 280 kg / cm) of the crusher is 198 tons, and on the mechanism, a crushing force of 1/3 is exhibited. In addition, even when a “pivoting force” by the combined operation of the boom, arm, and bucket produced by the hydraulic excavator is applied to the toe portion of the arm, the SKD 61 welded as the toe portion of the arm cannot be removed.

In addition, at the dismantling work site, even if the arm of a 120 kg class high-tensile steel plate with a cross-sectional area of about 100 mm x 300 mm may break,
The SKD61 welded to the tip of the arm could not be removed.

  In actual dismantling sites, it is possible to extend the wear life about 2 to 3 times that of the conventional one, and the smaller the crusher with the smaller crushing force, the longer the claw claw toe part has a longer life. It has been confirmed.

  As described above, according to the claw toe portion of the crushing claw used in the crusher of the present invention, it is possible to save the crusher by replacing the crusher to the site, or eliminating the need for on-site welding repair, extending the repair interval of claw tip replacement, etc. It becomes possible to realize resource recycling and reduction of environmental load.

  Hereinafter, as a specific example, a method of welding the tip of the claw claw using the SKD61 as a toe portion will be described.

  As shown in FIG. 1 or FIG. 2 (a), (b), when welding the toe part 3 to the crushing claw 2, the tip top part 2a of the crushing claw 2 and the rear end top part 3a of the toe part 3 by the SKD 61 are mutually connected. The groove angle is formed so that, for example, α = 60 °. Moreover, as shown in FIG. 3 or FIG. 4 (a), (b), the clearance gap D (D = about 3-4 mm) is provided between the front-end | tip top part 2a of the crushing claw 2, and the rear-end top part 3a of the toe part 3. Establish and face each other.

  In addition, the flow stop plate 5 is brought into contact with the side surface 2 b near the tip of the crushing claw 2 and the side surface 3 b near the rear end of the toe portion 3. As shown in FIG. 3, this flow stop plate 5 is welded to the flow stop plate 5 with both side portions of the tip crest 2 a of the claw claw 2 as fixed portions 5 a and 5 a. Further, steps 3c and 3c are formed on the side surface of the toe portion 3, and the flow stop plates 5 and 5 fixed on both sides of the crushing claw 2 as described above are held in a state where they are in contact with the steps 3c and 3c.

  Next, in this example, welding of SKD61 which is a welding material (toe part 3) and cast steel or high-tensile steel which is a base material (crushed claw 2) will be described.

  First, since preheating is set up, it starts at a higher temperature of 600 ° C. and warms both the base material and the SKD 61. Note that if the SKD 61 is temporarily attached (dotted) in a cold state, heat is taken away from the welded portion toward the SKD 61 side. Further, if the SKD 61 is temporarily attached by doting, deformation occurs in the welded portion, and thus a device for restraining the deformation so that deformation does not occur is necessary.

  Since the preheating start temperature of 600 ° C. is very easy to cool, it is necessary to perform rapid welding and setup in order to maintain the temperature between passes. Therefore, reheating may be required to ensure preheating at a predetermined temperature.

  As shown in FIG. 1 or FIG. 2 described above, as an example, the gap is 60 °, and a gap D of about 3 to 4 mm is provided between the tip top 2a of the crushing claw 2 and the rear end top 3a of the claw 3. As shown in FIG. 3 or FIG. 4 (a), (b), the center location of the tip top 2 a of the claw claw 2 and the rear end top 3 a of the claw tip 3 is fixed by spot welding 6.

  Next, as shown in FIGS. 5A to 5D (the flow stop plate 5 is omitted in this figure), the front end portion of the claw claw 2 and the rear end portion of the claw tip portion 3 are welded. That is, in this welding, as shown in FIG. 5 (b), when the first-layer welding 7a is performed on one side, the toe portion 3 is pulled toward the welding 7a side due to the shrinkage accompanying cooling of the welding 7a. It inclines like the part 3d.

  Further, as shown in FIG. 5 (c), by performing welding 7b on the opposite side of the weld 7a, the toe portion 3 is pulled to the welding 7b side opposite to the above by contraction accompanying cooling of the welding 7b. Then, it returns like the toe portion 3e. And it is possible to make the finished surface 9 by carrying out such welding several layers alternately on both sides, and shaving the surpluses 8a and 8b generated as shown in FIG. 5 (d) with a grinder.

  As said welding method, it welds so that it may bite with a welding current of 270A-350A using a 1.2 mm solid wire. At this time, care must be taken so that no flux or impurities are involved in welding. Also, the jet chisel that causes the flux or the like to act on the compressed air should not be applied to the SKD 61. The reason is that when the core of the jet chisel contacts the SKD 61 at high temperature, the SKD 61 is easily scratched, and this scratch may cause cracking.

  In the surface layer welding, extra current is applied at a current of about 270 A, and the welding step is eliminated by grinder finishing. Furthermore, in the state of 600 ° C., a surface hardening rod (Brinell hardness of about 600) is quickly welded to the weld. However, care should be taken not to weld the surface hardening rod to SKD61.

  Next, annealing after welding will be described.

  After the above welding, adhered spatter, flux, scale attached to SKD61, etc. are quickly removed using a grinder. Then, it is heated to an annealing temperature (820 ° C. to 870 ° C.) with flame hard (flame quenching) so as not to cool as much as possible. After this heating, slow cooling is performed while keeping warm with 40 mm thick glass wool. After that, the scale that springs up on the surface of the SKD 61 is removed to make it in a solid white state. This is because if the scale remains, uneven baking during quenching occurs.

  Next, quenching will be described.

  After the above-described slow cooling, it is confirmed that the welded portion is lowered to room temperature, and after quenching and heating, air cooling is performed. The quenching temperature is 1020 ° C. to 1050 ° C., but in the case of frame hard (flame quenching), the limit is about 900 ° C. Accordingly, the hardness does not increase and the hardness becomes about HRC 47 to 48, but the toughness is rather increased. Next, after this quenching, air cooling is performed, it is confirmed that the temperature is normal, and the scale is removed using a grinder.

  Next, tempering will be described.

  Tempering heating is performed at 550 ° C to 600 ° C. In this tempering heating, it is necessary not to raise the surface temperature of the SKD 61 at once, but to raise the temperature from the core in the SKD 61 by gradually raising the temperature. For this reason, in the case of frame hard (flame quenching), heating is performed with a long flame. After air-cooling after this heating, it is inspected for cracks and tempering is terminated.

  The peculiarity of the heat treatment relating to SKD61 in the present invention will be described.

  Originally, the heat treatment data related to SKD61 is heat treatment data of only SKD61, and conventionally, there is no heat treatment data in a state in which SKD61 and a base material are welded. Therefore, it seems that the heat treatment performed on the SKD 61 needs to be close to the heat treatment data of only the SKD 61 even though the base material is attached.

  For example, since the SKD 61 is smaller than the base material, the temperature rises quickly. Therefore, since the heat is transferred to the base material and rapidly cooled, it is necessary to heat the base material. In actual heating, the vicinity of the weld between the base material and the SKD 61 is heated to avoid rapid cooling.

Conversely, the cooling time can be adjusted by controlling the temperature of the base material,
Hardness control can be performed. In addition, temperature management is necessary for temperature changes in the four seasons such as summer and winter. For example, in the summer, preheating (heating) of the base material is conservative. In winter, the base metal is sufficiently preheated, and in some cases, the welding environment is covered with a panel or the like so that air does not flow. Further, it is necessary to raise the temperature of the welding environment by using a stove or the like.

  Furthermore, the heating method varies depending on the temperature of the working day and the volume of the base material, but in any case, it is necessary to keep the continuous cooling transformation curve related to the SKD 61 in FIG. In addition, the continuous cooling transformation curve shown in FIG. 6 has a component content (%) of C: 0.37, Si: 1.01, Mn: 0.42, Cr: 5.20, Mo = 1.12, It is a continuous cooling transformation curve regarding SKD61 of V: 0.85 and austenitization: 1030 degreeC * 10min. The hardness HRC obtained corresponding to each cooling time shown in this figure is 66.4, 65.8, 65.5, 65.2, 63.7, 62.5, 54.6, 52.4, 46. It is possible to ensure the toughness of the SKD61 by taking a cooling time so that the hardness of the SKD61 is about HRC 47 to 48.

  The crushing claw and the welding method of the crusher for building demolition of the present invention improve wear resistance by forming the toe portion of the crushing claw of the crusher used for building demolition as a high-hardness and high-toughness material with SKD61. It can be used as a crushing claw and a welding method for a crusher for building demolition.

1 arm 2 crushing claw 2a crest claw tip top 2b crushing claw side face 3 toe part (SKD61)
3a Rear end top portion 3b of the toe portion Side surface 3c of the toe portion Step 3d Inclined toe portion 3e Returned toe portion 4a Welded portion 4b of the toe portion and crushing claw 5 Welded portion of crushing claw and arm 5 Flow stop plate 5a Flow stop Plate fixing part 6 Spot welding 7a First-layer welding 7b First-layer welding 8a, 8b on the opposite side Extra surface 9 Grinder-finished surface D Clearance between the top of the claw claw and the top of the back of the toe

Claims (4)

In order to improve the wear resistance of the crushing claw that forms the tip of the arm of the crusher for building demolition, SKD61 is used as a material of high hardness and toughness from among hot die tool steel, and the SKD61 is crushed. A crushing claw for a building dismantling crusher, wherein a toe portion is formed by SKD61 by welding to the tip of the claw. 2. The crushing claw of a crusher for building demolition according to claim 1, wherein the toe portion is formed by welding SKD61 to the tip of the crushing claw. A single crushing claw was formed by welding the SKD61 constituting the toe portion to the tip of a crushing claw provided separately from the arm of the crusher, and the rear end of the single crushing claw was damaged or worn out. 2. The crushing claw of the crusher for building demolition according to claim 1, wherein the claw is welded to the tip. When the toe portion is formed by welding the SKD 61 to the tip of the crushing claw, a groove angle is provided between the tip of the claw claw and the rear end of the toe portion by the SKD 61, and the crest claw tip top portion and the rear end top portion of the toe portion are provided. In a state where a gap is provided between the crushing claw and facing each other, the center portion of the claw claw tip top and the crest claw tip center are spot-welded, and the side surface near the claw claw tip and the claw tip A crushing claw welding method for a crushing crusher for building demolition, characterized in that the tip of the claw claw and the rear end of the claw tip are welded to each other in a state where the flow stop plate is applied to the side surface near the rear end of the building. .